Backup Crew

Flight

The launch was originally planned for October 14, 1993. Due to a
computer failure this attempt was cancelled. The second attempt one day later
was cancelled again - this time due to a S-Band transponder failure.

The Space Shuttle Columbia mission
STS-58 was the second Spacelab flight dedicated to
life sciences research. Columbia's seven crewmembers performed a series of
experiments to gain more knowledge on how the human body adapts to the
weightless environment of space.While in Earth orbit, almost every human
physiological system undergoes some form of adaptation. Understanding the
causes of these changes will aid
NASA in the effort to fly longer missions as well as
give researchers insight into medical problems experienced by individuals on
Earth.The
STS-58 crew performed experiments focusing on the
cardiovascular, regulatory, neurovestibular and musculoskeletal systems of the
body. The experiments performed on Columbia's crew and on laboratory animals
(including 48 rats), along with data collected on the
SLS-1
mission (STS-40) in June 1991, provided
the most detailed and interrelated physiological measurements acquired in the
space environment since the
Skylab program in 1973 and 1974.

Spacelab
Life Sciences 2 consisted of 14 experiments focusing on the cardiovascular,
regulatory, neurovestibular and musculoskeletal systems of the body. Eight of
the experiments used the astronaut crew as subjects and six used rats. A broad
range of instruments - some, unique hardware and others, standard equipment -
were used for the human subjects throughout the mission. Equipment items
included a Gas Analyzer Mass Spectrometer, rotating dome and a rotating chair,
a Body Mass Measuring Device, Inflight Blood Collection System, Urine
Monitoring System, strip chart recorders, incubators, refrigerator/freezers, a
low-gravity centrifuge and an echocardiograph.The primary goal of the
SLS-2
mission was to conduct experiments in a variety of disciplines to address
important biomedical questions related to physiological responses to
microgravity and subsequent readaptation to gravity. The science also is
constructed to ensure crew health and safety on missions of up to 16 days in
duration. A third goal of
SLS-2
was to demonstrate the effectiveness of hardware standardization in experiment-
to-rack interfaces for future applications on Space Station.

Throughout
the space program, cardiovascular "deconditioning" has often been observed in
spaceflight crews. This diminished capacity of the cardiovascular system is
evidenced by decreased orthostatic tolerance, or lightheadedness, upon return
to Earth's gravity and is usually accompanied by increases in resting heart
rate and decreases in pulse pressure post-flight.Measurements of body
fluids in microgravity reveal a redistribution of circulating blood and body
water toward the head and neck area. The fluid redistribution fools the body
into thinking there is too much fluid and results in a reduction of fluid
volume. This overall shift may influence cardiovascular parameters such as
cardiac output, arterial and venous pressure and stroke volume. Upon return to
Earth, the cardiovascular system must readapt rapidly. This challenges the
space-adapted cardiovascular system, which contains less blood volume than
normal and sometimes results in orthostatic intolerance.Scientists also
believe that microgravity may alter lung function in orbit and are
investigating the effect that weightlessness has on the pulmonary system,
particularly on respiration, blood flow and gas exchange. The
SLS-2
cardiovascular/cardiopulmonary experiments seek to understand and quantify
these changes that occur on orbit and focus both on the acute fluid shift and
the long-term adaptation of the heart and lungs.

Investigations of
regulatory physiology in space included studies of both the renal/endocrine and
hematological systems.The amount of fluids and the pressures inside veins
and arteries is well-regulated by the kidneys and hormones of the
renal/endocrine system. On Earth, gravity affects the distribution of fluids
inside the body by pulling the various body fluids down toward the feet. But in
space, fluids redistribute upwards toward the chest and the head. This
perceived increase causes multiple physiological changes in the kidneys and
associated fluid regulating hormones in the cardiovascular system and in the
blood system.The
SLS-2
regulatory physiology experiments investigated the theory that the kidneys and
endocrine glands adjust the body's fluid regulating hormones to stimulate an
increase in fluid to be excreted. Over a longer period of time, the kidneys and
hormones establish new levels of salts, minerals and hormones appropriate for
the reduced fluid volume. The fluid shift also impacts the blood system
initially by a decrease in the plasma volume. Another effect of spaceflight is
a decrease in red blood cells which are responsible for carrying oxygen to the
tissues. Investigators hope to better understand the mechanisms behind these
changes after
SLS-2.

Neurovestibular changes related to equilibrium and body orientation
affect astronauts early in flight probably more than any other physiological
changes. The awareness of body orientation on Earth is attributed, in part, to
the detection of gravity by the otolith organs in the inner ear. Gravity
sensors in the joints and touch sensors in the skin also are involved, and the
eyes contribute by sensing the body's relationship to other objects. In space,
however, the weightless environment no longer corresponds with the visual and
sensual cues set to the brain, causing disorientation.Space motion sickness
may result from this disorientation, and although astronauts adapt within a few
days, investigators are working to better understand and counter these negative
effects. A similar disorientation of the balancing organs can occur when crew
members readapt to Earth's gravity after landing.The
SLS-2
neuroscience investigations seek to document both physical vestibular changes
and perception changes and to investigate the mechanisms involved.
Investigators also hoped to identify countermeasures to alleviate the effects
of space motion sickness.

In microgravity, the body's bones and muscles
are not used as extensively as they are on Earth. As a result, researchers have
seen a decrease in the mass of both during spaceflight.Human muscle atrophy
has been noted frequently among returning astronauts and can be characterized
by a loss of lean body mass, decreased muscle mass in the calves and decreased
muscle strength. Despite an adequate protein intake, the effects of spaceflight
appear analogous to those of the fasting state when muscle protein is broken
down into its constituent amino acids.Researchers also have identified a
progressive loss of skeletal mass in microgravity. This is associated with
changes of calcium homeostasis as is evidenced by increased urinary and fecal
excretion of calcium. Efforts to avoid the loss of skeletal density through
exercise have been only partially successful, and researchers have not been
able to reverse calcium and nitrogen loss.On return to Earth after
short-duration missions, these responses are shown to be reversible, but the
effects on muscles and bones during long-duration missions yet are not well
known. The SLS-2 studies provided more information about this
complex system.

The EDO Medical Project was designed to assess the
impact of long duration spaceflight (10 or more days) on astronaut health,
identify any operational medical concerns and test countermeasures for the
adverse affects of weightlessness on human physiology.Three of the tests
took place inflight - DSO 611, "Air Monitoring Instrument Evaluation and
Atmosphere Characterization"; DSO 612, "Energy Utilization"; and DSO 623,
"Lower Body Negative Pressure (LBNP) Countermeasures". The others occurred
before and/or after the mission.The LBNP activity employed a bag in which a
vacuum can be created. The bag encased the lower body and sealed at the waist.
By lowering the pressure within the bag, the subject's body fluids were drawn
into his lower extremities, mimicking the natural fluid distribution that
occurs on Earth. This conditions the cardiovascular system for the fluid shift
that occurs upon re-entry and improves orthostatic tolerance.William
McArthur and John
Blaha
began using the Lower Body Negative Pressure device on flight day 3, which is
being tested as a countermeasure for the detrimental effects of microgravity.
All three flight crew members will collect urine and saliva samples and keep
logs of their exercise and food and fluid intake as part of the Energy
Utilization detailed supplementary objective. DSO 612 looks at the nutritial
and energy requirements of crew members on long-duration space flights and the
relationship between fluid and food consumption.

Crew members conducted
experiments aimed at understanding bone tissue loss and the effects of
microgravity on sensory perception. Two neurovestibular experiments
investigating space motion sickness and perception changes were performed on
the 2nd day as well. Astronauts Shannon
Lucid and Martin
Fettman wore a headset, called an Accelerometer recording
Unit, designed to continually record head movements throughout the
day.

Only one minor issue came up on October 19, 1993 associated with a
circuit breaker that tripped, cutting off power temporarily to one of the
rodent cages in the module. Flight controllers in Houston reported it was not
caused by a short in the electrical system and the breaker was reset, restoring
power to the cage.

On October 20, 1993, though the space toilet is
working fine, the crew detected a slight leak around the filter door before
going to bed. They removed the filter and cleaned up about a teaspoon of water
- much less than had been expected. As a precaution, a secondary fan separator
unit was used to separate fluid from the air before cycling the air back into
the cabin through the filter.

On October 21, 1993, Payload Commander
Rhea Seddon, Mission Specialists Shannon
Lucid and David
Wolf
and Payload Specialist Martin
Fettman collected additional blood and urine samples for the
series of metabolic experiments. Some of the samples will follow-up on the
calcium absorption experiment performed yesterday. The experiment, sponsored by
Dr. C.D. Arnaud of the University of California at San Francisco, studies the
mechanisms of how calcium is maintained and used in bone metabolism in space.
Based on preliminary results from the 1991
SLS-1
mission, Dr. Arnaud believes the decrease in bone density is due to increased
bone breakdown that is not compensated for by a subsequent increase in bone
formation.

Students in the United States and France had a chance to
speak via amateur radio with astronauts aboard the Space Shuttle Columbia
during
STS-58 (SAREX). Ground-based amateur radio operators
("hams") were able to contact the Shuttle through automated
computer-to-computer amateur (packet) radio link. There also were voice
contacts with the general ham community.On October 22, 1993, using the
on-board ham radio called
SAREX for Shuttle Amateur Radio Experiment, John
Blaha
and Richard
Searfoss contacted school children at the Sycamore Middle
School in Pleasant View, Tennessee, and Gardendale Elementary in Pasadena,
Texas. The Standard Interface Rack, or SIR, was tested today by Richard
Searfoss to demonstrate that equipment can be removed from
one rack location and reintegrated into another by a single crew member during
orbital operations while maintaining reliable mechanical, data and power
interfaces.

On October 27, 1993, Pilot Richard
Searfoss put Columbia through some maneuvers as part of the
Orbital Acceleration Research Experiment. The main goal of the
experiment is to accurately measure the aerodynamic forces that act on the
shuttle in orbit and during the early stages of entry. The information will be
useful to scientists and engineers planning future Spacelab microgravity
research flights in which experiments will need a quiet, motion- free
environment to produce the best possible data.

The main goal of the
OARE experiment was to measure the Shuttle's aerodynamic forces (drag)
in orbit and during the early stages of reentry. The OARE sensor was capable of
discerning accelerations as small as onebillionth of the Earth's surface
gravitational acceleration (i.e. 1:109).OARE was designed to calibrate
itself on-orbit so that absolute values of these low accelerations can be
measured. All previous accelerometers onboard the Shuttle depended upon ground
calibrations. This, of course, is done in a 1-g field on Earth and past
experience has shown that, for the level of precision required for the OARE
objectives, ground calibrations are not adequate.The OARE flight hardware
consisted of 4 electronics boxes and a table assembly with a container mounted
on its surface. This container housed the electrostatic-suspended proof-mass
accelerometer sensor. The whole system weighed about 107 lbs. (48.5 kg) and was
17 x 13 x 41 inches (0.43 x 0.33 x 1.04 meter) and required about 110 watts of
power.

One of the challenges of flying long duration Shuttle missions is
the issue of orbiter landing tasks. These tasks require a high level of skill
and proficiency yet data shows that a pilot's landing skills degrade after an
extended absence from a landing trainer such as the Shuttle Training
Aircraft.During Shuttle Mission
STS-58, a portable scientific workstation designed to
aid the Shuttle commander and pilot in maintaining those landing skills was
demonstrated for the first time.The Pilot In-Flight Landing Operations
Trainer (PILOT) system hardware consisted of a portable scientific
workstation, a high resolution color display and a hand controller with orbiter
look and feel. The software used in the system was transferred from the Shuttle
Engineering Simulator software used to validate Shuttle flight software. This
provided PILOT with orbiter handling and guidance characteristics.